The Issue:

“The chance of large-scale coastal flooding episodes is increasing. In the last few decades, sea levels have been rising steadily at about 3 centimeters per decade and many estimates expect that this rate will accelerate going forward. At the same time, the population living in coastal counties in the United States grew by 40 percent between 1970 and 2010 and is projected to continue rising. Are people considering the increased risk of flooding associated with sea level rise in their housing decisions? Looking at what happened to property values in New York City after Hurricane Sandy gives us a first look at how those on the front lines may be responding.”

The Facts:

“Past research has found the response of homebuyers towards flooding risks and the threat of other climate-related hazards to be short-lived. While a region’s exposure to hurricanes or flooding does not vary greatly from one year to the next, many studies have found that homebuyers tend to take these risks much more into account immediately following hurricanes and other catastrophic events. However, these effects tend to be short-lived —very often vanishing completely within five years (see here and here). Flood insurance take-up rates, for instance, have tended to spike the year after a flooding event and then gradually decline to the levels that prevailed before the flood. This response happened not only in the flooded zones but – to a lesser extent — also in non-flooded areas in the same television media markets according to one study. While the risk of flooding remains objectively the same, people may be more aware of it following a flood and then tend to forget about it with the passage of time. It is also possible that, as time goes by, new people who have had less direct exposure to the risk move into the area. These facts suggest a gap between objective probabilities of flood risk and households’ perceptions of this risk. In addition to the psychological biases mentioned, coordination problems, misguided policies, and the expectation of financial assistance by the government in case of disaster might contribute to a mismatch between home prices and damage risk.”

“Hurricane Sandy was a climatic event of unprecedented proportions that impacted the Greater New York region. The storm hit New York on October 29, 2012. At the time, Sandy was the largest Atlantic hurricane on record and the second costliest in U.S. history (behind Hurricane Katrina), with damages amounting to over $19 billion. Hurricane Sandy flooded 17 percent of New York City (or nearly 90,000 buildings).”